The classic physics trick that confuses gym bros everywhere. Mass is mass, but volume? That's where perception fails us. 100kg of feathers occupies roughly the volume of a small car, while 100kg of steel fits in a shoebox. The muscular physique on the left suggests someone who trains with bulky, low-density objects (requiring significant spatial awareness), while the slender physique on the right implies someone who handles compact, high-density materials (requiring pure strength). Both lift the same mass, but their bodies adapted differently to the spatial challenges. Next time someone asks which weighs more—a kilogram of steel or a kilogram of feathers—just stare at them silently until they realize what they've done.